Telegraphy.



' P. B. DELANY.

TELEGRAPHY.

APPLICATION FILED SEPT. 9. mo.

Patented Nov. 30

WIT NE 8856:

0 4, 5, 6, 7, 8 and TELEGRAPHY.

Specification of Letters Patent.

Patented Nov. 30, 1915.

Application filed September 9, 1910. Serial No. 581,216.

To all whom it may concern: v

Be it known that I, PATRICK B. DELANY, a citizen of the United States, residing at South Orange, county New Jersey, have invented a new and useful Improvement in Telegraphy, of which the following is a specification.

This invention relates primarily to that automatic telegraph system in which transmission of signals is eflected'by means of a and a record of transmitted by electro-chemical action perforated tape signals made upon a tape.

The object of the invention is to improve the working of such lines by obviating the evil effects of electrostatic capacity and selfinductance or an. unbalanced proportion of these two conditions; and also'to protect the line against the evil inductive effects due to the proximity of conductors carrying high power currents.

To this end, the invention comprises an organization in which each signal, such as a dot or dash, is initiated by a current of one polarity and terminated by a current of the other polarity and wherein the line is at all times occupied by a current of either the one or the other polaritv. A line under the latter condition is one that may be termed locked or closed against disturbing inductive effects from adjacent high current conductors.

Combined with the arrangement gradual rise of potential at the beginning of each signal impulse, whether positive or negative, and a drop in potential at the end of each impulse.

In the accompanying drawing, which shows an organization that experience has demonstrated to be a practical and efiicient embodiment of the invention, Figure 1 is a diagrammatic view showing a sending and receiving station connected by a main line; Fig. 2, a diagrammatic view showing a modification of the arrangement at the sending station; Fig. 3 shows a section of transmitting tape with perforations for transmitting the word \Vashington; and Figs.

tape with records thereon.

of Essex, State of 1 thus fardescribed is a means whereby there is a- 9 show sections of receiving Referring to Fig. 1, 1 represents the tape drawin rolls of a transmitting apparatus.

2 in icates the perforated transmitting tape having two rows of perforations. Pairs of perforations in lines perpendicular to the tape represent dots and those in lines oblique represent dashes.

3 and 4: are upper and lower transmitting fingers opposed to each other and coming in contact through the lower series (as viewed in the drawing) :of the perforations; and 5 and 6 represent another pair of the opposed transmitting fingers coming in contact through the perforations in the upper row. The lower finger 1 is connected with the positivepole of the transmitting battery 13 and the other lower finger 6 is connected with the negative pole. The two upper fingers 3, 5, are electrically united and connected with the main line L and also through a conductor 7 and adjustable resistance 8 through the coils of a polarized relay R to earth. The stops 9 and 10, of the relay armature member are connected respectively with the negative and positive poles of battery B; and the armature member is connected through an adjustable resistance 11 with the main line L.

pendicular to the. tape, the opposed pair of contact fingers 5, 6, are placed a suitable distance in advance of the other pair of contact fingers, 3, 4. The signal initiating impulses are from the positive pole of the transmitting battery through the contact fingers 3, 4 to line, and the signal terminating impulses are from the negative pole of the transmitting battery to line through contacts 5, 6.

. In Fig. 1, the armature lever of relay R is against its stop 9, and the negative pole of battery B is connected to line through resistance 11. This is a condition that always exists at the time a signal impulse is to be sent. hen the contact fingers 3, 4 meet through the perforation, the positive pole of posed by the other pole of the battery connected at the moment to the line through resistance 11. Current from the positive pole of the battery now simultaneously passes through the coils of polarized relay R. I

The first eflect is, for a very brief instant, to impair the contact of the armature lever of the relay with its stop 9, thereby further reducing the opposition of the negative pole of the battery, and when the armature lever relay R leaves its stop 9, the strength of the impulse on the line from the positive pole of the battery rises to a maximum. When the contact fingers 3, 4 are separated by the body of the transmitting tape, the positive pole of the battery is still connected to line through the resistance 11, the armature lever of the relay being then against its stop 10. 'lVhen, however, the transmitting tape is advanced sufiiciently, contact fingers 5, 6 come together through the companion dot perforation in the upper series and the negative pole of the transmitting battery is connected to line through them and also to earth through the coils of the relay. The strength of the impulse from the negative pole of the battery at the beginning is opposed by the positive pole of the battery connected to line through the resistance 11, and when the relay armature passes again to its stop 9, the strength of the negative impulse-on the line is at a maximum. v

Fig. 2 indicates a modification in which i the coils of the relay are in series with the transmitting fingers and main line. The operation is the same generally as already described. The organization shown in Fig..

1 is, however, preferred.

"Fig. 4 is a representation of a receiving tape having the word Washington in dots and dashes thereon. The dots and dashes have been made in the ordinary way without'supplementing the current on the line after the contact fingers 3, 4 are separated. As the dots and dashes are represented by the space or interval of time between the positive and negative impulses transmitted through the perforations in the transmitting tape, the extension marking representing the dashes is due to the static charge in the line or, as it is usually called, tailing.

Fig. 5 shows a receiving tape with the same record, produced, however, by supplementing the initial marking impulse by the full strength of the current and maintaining the full strength upon the line until the reversal occurs.

Fig. 6 shows a transmitting tape with the same record made Where the supplementary Fig. 8 shows a like succession of dots made when the marking current has been supplemented and maintained upon the line.

Fig. 9 shows a receiving tape having upon it in dots and dashes this is the way produced by the use of two recording fingers 1 over a line looked as described against outside efiects by maintenance of current on the line at all times.

In the system abovedescribed, there is a practically closed or locked circuit in which E a current is always maintained, and a gradual rise of otential at the beginning of each impulse and a drop at the end. Static discharge afi'ecting the record is prevented by a continuance of the signal impulse weak- 8 ened to such a degree as to be sufficient not only for that purpose but. for a.reinforcement of the maximum potential of the impulse to permit of the record being continued to the neXt reversal. 9

As to induced currents from adjacent wires, with a non-marking ground connection at the receiver, those of a negative character would not show on the tape in any event while those of positive polarity would 9 coincide with the signal being recorded at the time; and inductive impulses of positive polarity occurring during the time that the negative battery current occupies the line (representing spaces between the elements 1 of a letter or spaces between letters and words) would be neutralized by the negative battery current maintained on the line. It will be seen that the weakened or attenuated battery currents are superseded at each 1 reversal by the stronger impulses and that at no time is the line disconnected from a source of current. The reversalthrough a perforation is not met by a current of equal strength at the relay contact but by a much 1 weaker one that is overcome without an appreciable period of neutrality: nor is the armature of the relay moved from its contact until the reversal has had time "to establish itself on the line simultaneously with 1 magnetization of the relay. Doubtless also the change from the weak current to the stronger reversal is not abrupt but is, on the contrary, gradual owing to the impedance of the relay coils and the change of '1:

pressure between the armature and its convtact so that at a speed of, say, about three hundred words a minute, the relay armature will have reached the opposite contact before the contact between the transmitting 1i fingers is broken by the edge of the perforation in the tape. The self-induction impulse from the polarlzcd relay winding following each signal is lost in the reduced current, or, it may be neutralized by a condenser in shunt around the relay in the ordinary way. Sparking at the transmitting contact fingers is prevented by the supplementary contacts at the relay and Will not occur at the relay contacts because of the weak current.

Since the dashes are formed "by, the supplementary impulses sent into the line from the relay contacts, and as these are comparatively weak, the static discharge'from the line becomes almost negligible and will not be suflicient to appreciably interfere with the next succeeding impulse.

I claim: 1

1. In telegraphy a method of transmission comprising maintaining a closed main circuit, impressing at all times thereon current of either positive or negative polarity and forming signal impulses by impressing on such circuit successively two fixed strengths of current of the same polarity, the signal producing currents being of uniform duration'and regularly alternating in polarity.

2. In telegraphy the method of transmission comprising maintaining a closed main' circuit, impressing thereon at all times ourrentof either positive or negative polarity and beginning a signal impulse with a current weakened by an opposing current, continuing said signal impulse by the same current unopposed and ending said signal with the same current weakened by introduction of resistance.

3. In telegraphy the cuit, mitter in a parallel circuit trolled by said first transmitter, connections whereby each ters sends a portion of each signal into the circuit.

4. In telegraphy the combination of a combination of a cirwith and conand circuit senting signals,

a transmitter in said circuit, a trans-' of said transmit telegraph circuit, a perforated tape repreletters and spaces, an. automatic transmitter sending said.signalsinto said circuit, an electromagnet controlled b? said automatic transmitter and means controlled by said electromagnet for prolonging the impulses sent into the circuit by said automatic transmitter and for maintaining a current in said circuit during the time represented by spaces between impulses, letters and words.

5. In telegraphy the combination of a perforated tape representing signals, an automatic transmitter for sending signals represented on the tape into a circuit, a polarized relay actuated by said automatic transmitter for'also sending impulses into the circuit which latter impulses prolong the impulses sent into the circuit by the automatic transmitter.

6. In telegraphy the method of forming a signal consisting of beginning said signal with a current partially weakened by a current of opposite polarity, discontinuing said current of opposite polarity and continuing said signal by the same current of full strength, reducing said current and ending said signal by reduction of said reduced current by. an opposing and reversing current.

7. The combination of a perforated tape 

